Cans from several presses are often accumulated on a single pallet. Hence, since some can defects are not discovered until the cans are palletized, it is difficult to tell which press a given can came from and which cans were made on a possibly defective press. Hence, it is desirable that each can be somehow marked to identify the press from which it originated.
In the past, attempts have been made to identify the press-origin of given cans by marking the bottoms in some way. One such method was to use selectively placed nicks in the bottoms of the cans to identify their having originated from one press or another. Other attempts were made to mark the cans by embossing the bottoms between a punch and die. Both of these methods, however, resulted in objectionable stress concentrations. The instant invention, however, provides a structure and method for embossing the bottoms of cans without appearing to cause detrimental stress concentrations.